Automated biopsy instruments

ABSTRACT

The present invention provides automated biopsy instruments especially useful for improving minimally invasive medical procedures to obtain soft tissue biopsy samples. The biopsy instruments provide side-by-side actuators which retract a stylet and a cannula in specific sequences. The biopsy instruments may include a single spring or two springs to sequentially fire the stylet and the cannula.

FIELD OF THE INVENTION

This invention generally relates to biopsy instruments. Morespecifically, this invention relates to automated biopsy instrumentsespecially useful for improving minimally invasive medical procedures toobtain soft tissue biopsy samples.

BACKGROUND OF THE INVENTION

A soft tissue biopsy procedure is a medical procedure for removing asoft tissue sample from a human or animal. The tissue sample can beanalyzed to assist a medical professional in formulating a diagnosis.The biopsy procedure is a minimally invasive procedure for obtaining thetissue sample.

The biopsy procedure can be performed utilizing various techniques anddevices. Typically, a biopsy device includes an inner stylet slidablypositioned inside an outer cannula. The stylet is a solid, pointedneedle having a tissue sampling recess, and the cannula is a hollow,open ended needle having a sharp tip. The stylet and the cannula aremanipulated to capture a tissue sample in the sample recess. Existingbiopsy devices include manual, semi-automated, and automated devices.

Manual biopsy devices allow for manual movement of the stylet and thecannula. Initially, the stylet and the cannula are inserted into softtissue with the cannula covering the stylet tissue recess. Next, thestylet is manually advanced into the soft tissue to expose the tissuerecess and to allow tissue to prolapse into the recess. The cannula isthen manually advanced to sever the tissue and capture a tissue samplewithin the recess. Next, the stylet or the entire the biopsy device iswithdrawn from the patient and the tissue sample removed from therecess.

Existing manual biopsy devices have exhibited drawbacks. For example,manual devices require the use of two hands to advance the stylet whileholding the cannula in position, and to hold the stylet in positionwhile advancing the cannula. This biopsy technique requires great manualdexterity and coordination. Further, the cutting speed of the manuallyadvanced cannula is quite slow which may result in a poor quality tissuesample.

Existing semi-automatic biopsy devices provide stylet and cannulaadvancement motions similar to manually operated devices. After thestylet is manually advanced, the semi-automatic devices typicallyinclude a compression spring that advances the cannula to capture atissue sample. The semi-automatic devices still require manualmanipulation of the stylet.

Existing automatic biopsy devices also provide stylet and cannulaadvancement motions to capture a tissue sample in a stylet samplerecess. The automatic devices generally include two compression springsto advance the stylet and the cannula. A first compression springadvances the stylet forward after a firing button is depressed. A secondcompression spring subsequently advances the cannula forward to severand capture a tissue sample. Existing automatic devices have exhibiteddrawbacks. For example, automatic devices have required the use of twohands to cock the device (compress the springs). One device purports tobe cockable with a single hand; but, the hand must change positionsafter cocking the cannula in order to cock the stylet. Changing handpositions is cumbersome and encourages two handed cocking. Additionally,as a compression spring expands, the spring force decreases. As thespring force decreases, the stylet and cannula speeds decrease, whichmay compromise the quality of the tissue sample. Also, existingautomatic devices have provided insufficient time to allow the tissue torelax into the sample recess. Consequently, the size of the tissuesample may be reduced.

Existing biopsy devices have been designed to be either reusable ordisposable. The reusable devices include a reusable handle anddisposable needle assemblies. The stylet and cannula are removable fromthe handle and disposable with a new stylet and cannula. The handle canbe cleaned and re-sterilized after use and thus, is reusable. Disposabledevices include a permanent stylet and cannula and are notre-sterilizable. Accordingly, disposable devices are used on a singlepatient and then discarded.

Examples of existing biopsy devices are disclosed in U.S. Pat. Nos.4,600,014; 4,944,308; 4,958,625; 5,368,045; and Re34,056. A reusableautomatic device containing a single spring for stylet and cannulaadvancement is disclosed in U.S. Pat. No. 5,121,751.

Therefore, needs exist to improve biopsy devices. Particularly, needsexist to improve automated biopsy instruments especially useful forminimally invasive medical procedures to obtain soft tissue biopsysamples. The present invention satisfies these and other needs toimprove biopsy devices.

Other aspects and advantages of the present invention will becomeapparent after reading this disclosure, including the claims, andreviewing the accompanying drawings.

SUMMARY OF THE INVENTION

The present invention provides automated biopsy instruments especiallyuseful for improving minimum invasive medical procedures to obtain softtissue biopsy samples. The biopsy instruments provide side-by-sideactuators which retract a stylet and a cannula in specific sequences.The retraction sequences include cannula retraction with subsequentstylet retraction, and simultaneous cannula and stylet retraction. Theside-by-side design of the cannula and stylet actuators allow the biopsyinstrument to be operated with a single human hand without repositioningthe hand.

The biopsy instruments may include a single spring or two springs tosequentially fire the stylet and the cannula. A constant force spring isutilized in the single spring embodiment. The single spring embodimentalso includes an engagement mechanism connected to the constant forcespring. The engagement mechanism first fires the stylet, initiatesconcurrent cannula firing, and then completes cannula firing. The biopsydevice provides a time delay to allow tissue to more effectivelyprolapse into the stylet tissue sample recess.

A safety cover is also provided to prevent accidental firing of thebiopsy instrument.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a biopsy instrument made in accordancewith the principles of the present invention.

FIG. 2 is a cross-sectional, perspective view of a biopsy instrumentmade in accordance with the principles of the present invention.

FIG. 3 is a cross-sectional view of the biopsy instrument of FIG. 2 in acannula retracted mode.

FIG. 4 is a cross-sectional view of the biopsy instrument of FIG. 2 in acannula and stylet retracted mode.

FIG. 5 is an enlarged, cross-sectional view of an interlockingmechanism.

FIG. 6 is an exploded, perspective view of an alternative embodiment ofa biopsy instrument made in accordance with the principles of thepresent invention.

FIG. 7 is a perspective view of another alternative embodiment of abiopsy instrument made in accordance with the principles of the presentinvention.

FIG. 8 is a perspective view of the biopsy instrument of FIG. 7 in acannula retracted mode.

FIG. 9 is a perspective, partial cross-sectional view of the biopsyinstrument of FIG. 7 in a cannula and stylet retracted mode.

DETAILED DESCRIPTION OF THE INVENTION

Although the present invention can be made in many different forms, thepreferred embodiments are described in this disclosure and shown in theattached drawings. This disclosure exemplifies the principles of thepresent invention and does not limit the broad aspects of the inventiononly to the illustrated embodiments.

FIG. 1 shows a perspective view of a biopsy instrument 10 made inaccordance with the principles of the present invention. The biopsyinstrument 10 includes a housing 12 having a left housing 14 and a righthousing 16. The housing could be made from other components, forexample, an upper housing and a lower housing as shown in FIG. 6.Referring to FIG. 1, preferably, the housing 12 is ergonomicallydesigned to conform to the human hand and may include one or more fingerrests 18. The ergonomic design includes a housing shape that coincideswith contours of the human hand and is comfortable to hold. The biopsyinstrument 10 also includes a cannula actuator 30, a stylet actuator 32,and a safety cover 34 as described below.

A cannula 20 and a stylet 22 are slidably contained within the housing12 and extend out of an opening 24 in a housing end 26. The cannula 20is a hollow needle having a sharp, open end. The stylet 22 is a solidneedle having a pointed end and a tissue sample recess 28. The recess 28is shown in FIG. 3. The stylet 22 is slidably positioned within thecannula 20 and extends beyond the cannula end.

FIG. 2 shows a cross-sectional, perspective view of a biopsy instrument10 made in accordance with the principles of the present invention. Thecannula 20 and the stylet 22 are permanently attached to two self-guidedslides, a cannula slide 36 and a stylet slide 38, respectively. Thecannula and stylet slides 36, 38 are axially slidable on a guide 40connected to the housing 12. There may be two guides 40, one guide 40 oneach half of the housing. The stylet slide 38 is slidable between a rearstop block 42 and a middle stop block 44, and the cannula slide 36 isslidable between the middle stop block 44 and a front stop block 46. Thefront, middle, and rear stop blocks 42, 44, 46 are permanently securedto the housing 12 at their respective locations.

Accordingly, the stylet slide 38 is slidable between a first positionadjacent the rear stop block 42 and a second position adjacent themiddle stop block 44. The cannula slide 36 is slidable between a firstposition adjacent the middle stop block 44 and a second positionadjacent the front stop block 46. When the stylet slide 38 and thecannula slide 36 are in their first positions, a portion of the stylet22 and a portion of the cannula 20 are retracted into the instrument 10.When the stylet slide 38 and the cannula slide 36 are in their secondpositions, the stylet 22 and cannula 20 are advanced out of theinstrument 10.

A constant force spring 48 provides the driving force for the stylet 22and the cannula 20. The constant force spring 48 maintains a constantspeed of travel for both the stylet 22 and the cannula 20. The constantforce spring 48 is a rotatable and flexible spring coil. Also one ormore constant force springs 48 can be utilized by connecting themultiple springs at their non-coiled ends. Accordingly, multiple springs48 having relatively small coil diameters can be utilized to supply thesame force as a single spring 48 having a relatively larger coildiameter. The coiled end of the spring 48 is secured to the housing 12and the free end of the spring 48 slidably extends through a passageway50 in the cannula slide 36 and is attached to an engagement mechanism52.

The engagement mechanism 52 includes an interlock end 54 and a camsurface 56. The cam surface 56 of the engagement mechanism 52 cams alonga ramp 58 to alternatively interlock and release the interlock end 54with the stylet slide 38 as described in detail below. The engagementmechanism 52 may include multiple cam surfaces 56 that cam alongmultiple spaced apart ramps 58, as shown more clearly in FIG. 6, forexample.

Referring to FIG. 2, the cannula actuator 30 and the stylet actuator 32are independent and slidably extend along the housing 12 and through ahousing opening 60. The stylet actuator 32 and the cannula actuator arejuxtaposed. Particularly, the cannula actuator 30 and the styletactuator 32 are positioned side-by-side each other to permit actuationof both actuators 30, 32 by a single finger of a single hand withoutrepositioning the hand. The actuators 30, 32 provide a mechanism toplace the biopsy device 10 in a ready mode as described in detail below.The actuators 30, 32 include a finger surface 62 which can be contactedby a single finger of a single human hand to actuate (slide) theactuators 30, 32. A projection 64 on the stylet slide 38 engages thestylet actuator 32. Likewise, a projection 66 on the cannula slide 36engages the cannula actuator 30.

A spring loaded firing trigger 68 is provided at a distal end 70 of theinstrument 10 opposite of the proximal front end 26. The firing trigger68 is pressed to fire the instrument 10. Particularly, the firingtrigger 68 fires and releases the stylet 22 as described below. Thehinged safety cover 34 (shown in FIG. 1) is provided to preventaccidental firing of the instrument. The safety cover 34 can be movedbetween a first position covering the firing trigger 68 and a secondposition allowing access to the firing trigger 68. The firing trigger 68could be placed at any location on the instrument 10, including theproximal front end, and an appropriate mechanism provided to fire theinstrument 10.

Operation of the biopsy instrument 10 will be described with referenceto FIGS. 2-5. Initially, FIG. 2 shows the instrument 10 in a fired mode.The biopsy instrument 10 is placed in a ready mode by holding theinstrument 10 in a single hand in a first position and actuating thecannula actuator 30 and the stylet actuator 32 to retract the cannula 20and the stylet 22.

Referring to FIG. 3, a cross-sectional view of the biopsy instrument 10in a cannula retracted mode is shown. First, the cannula actuator 30 isretracted rearwardly by a finger of the same single hand contacting thefinger surface 62. The cannula actuator 30 engages the projection 66 onthe cannula slide 36 and slides the cannula slide 36 and the cannula 20rearwardly against the force of the constant force spring 48. Theengagement mechanism 52 is abutted against the cannula slide 36 andthus, the spring 48 is uncoiled as the cannula actuator 30 is actuated.

FIG. 5 shows an enlarged, cross-sectional view of an interlockingmechanism in three stages. The first stage is shown where the cannulaslide 36 retracts, the cam surface 56 of the engagement mechanism 52 isadvanced and elevated along a first cam surface 58a of the ramp 58. Thesecond stage is when the cam surface 56 slides along a horizontal rampsurface 58c. The interlock end 54 of the engagement mechanism 52 isguided into a lock 72 on the stylet slide. The third stage is shown asthe engagement mechanism cam surface 56 advances and descends along asecond cam surface 58b of the ramp 58; the interlock end 54 releasablylocks to the lock 72 of the stylet slide 38.

Referring to FIG. 3, the cannula slide 36 contacts a first stylet latch74 and releases the stylet slide 38 from being latched to the middlestop block 44. The first stylet latch 74 is shown in FIG. 4 unlatched tothe middle stop block 44. As shown in FIG. 3, a cannula latch 76 latchesthe cannula slide 36 to the middle stop block 44. In this position ofthe instrument 10, the cannula 20 is retracted and the stylet tissuesample recess 28 is exposed. If a tissue sample had previously beencaptured within the recess 28, the tissue sample could now be expelled.

Referring to FIG. 4, a cross-sectional view of the biopsy instrument 10in a cannula and stylet retracted mode (instrument ready for firingmode) is shown. Second, while the same single hand remains in its firstposition on the instrument 10, the stylet actuator 32 is retractedrearwardly by the same finger contacting the finger surface 62 on thestylet actuator 32. The stylet actuator 32 engages the projection 64 onthe stylet slide 38 and slides the stylet slide 38 and the stylet 22rearwardly against the force of the constant force spring 48. Theengagement mechanism 52 is locked to the stylet slide 38 and thus, thespring 48 is further uncoiled as the stylet actuator 32 is actuated. Asecond stylet latch 78 latches the stylet slide 38 to the rear stopblock 42. In this position of the instrument 10, both the cannula 20 andthe stylet 22 are retracted and the biopsy instrument 10 is ready forfiring.

In the ready mode, the stylet 22 and the cannula 20 are inserted into apatient in the area where a tissue sample is desired.

The biopsy instrument 10 is fired by moving the safety cover 34 at therear end 70 of the housing 12 away from the spring loaded trigger 68 anddepressing the trigger 68. The trigger 68 releases the second styletlatch 78 and the spring 48 propels the stylet slide 38 and the stylet 22forward extending the stylet 22 into the tissue. The stylet recess 28 isexposed and the tissue prolapses into the recess 28. The stylet slide 38advances forward until it contacts the middle stop block 44, and at thatpoint the first stylet latch 74 latches onto the middle stop block 44.The first stylet latch 74 latches onto the middle stop block 44 toprevent the stylet 22 from recoiling as the cannula 20 advances forward.

As the stylet slide 38 approaches the middle stop block 44, the styletslide 38 impacts the cannula latch 76 and moves the cannula latch 76radially outward and axially forward. The forward axial movement of thecannula latch 76 initiates forward movement of the cannula slide 36 andthe cannula 20 simultaneously and concurrently with the forward travelof the stylet 22.

As the stylet slide 38 approaches the middle stop block 44, the camsurface 56 of the engagement mechanism 52 is elevated along the rampsecond cam surface 58b. After the cannula 20 has started its forwardmotion, the interlock end 54 is elevated sufficiently to be releasedfrom the stylet slide lock 72.

The engagement mechanism 52 continues to travel forwardly under theforce of the spring 48 and abuts the cannula slide 36. The constantforce spring 48 advances the cannula slide 36 and the cannula 22 untilthe cannula slide 36 contacts the front stop block 46. After theconcurrent stylet 22 and cannula 20 motion, the cannula 20 briefly stopsuntil the spring 48 resumes movement of the cannula 20. For example,there may be approximately a millisecond time delay. The time delayprovided by the engagement mechanism 52 and the ramp 58 allowsadditional time for the tissue to prolapse into the stylet recess 28.

As the cannula 20 advances over the stylet 22, the cannula 20 severs thetissue and captures a tissue sample within the recess. After the tissuesample is captured, the biopsy instrument 10 is removed from thepatient. The cannula 20 can be retracted as discussed above to exposethe tissue sample and remove the sample from the biopsy instrument 10.

The biopsy instrument 10 only permits a specific actuation sequence ofthe cannula 20 and the stylet 22. The cannula 20 must be retracted priorto retraction of the stylet 22 because in the fired mode, the styletslide 38 is latched to the middle stop block 44. The stylet slide 38 isunlatched from the middle stop block 44 only by the cannula slide 36contacting the first stylet latch 74. This prevents a captured tissuesample from being dragged along the inside of the cannula 20 anddamaged. In other words, the cannula actuator 30 is actuatedindependently of the stylet actuator 32, and subsequently the styletactuator 32 is actuated. The cannula actuator 30 and the stylet actuator32 return to their forward positions as shown in FIG. 1 as the stylet 22and the cannula 20 are fired.

FIG. 6 shows an exploded, perspective view of an alternative embodimentof a biopsy instrument 10 made in accordance with the principles of thepresent invention. Components of the alternative biopsy instrument 10shown in FIG. 6 are identified by the same reference numerals as used inFIGS. 1-5.

The biopsy instrument 10 shown in FIG. 6 includes an upper housing 14and a lower housing 16. A guide 40 is a separate component from thehousing. The stylet slide 38 and the cannula slide 36 slide along theguide 40. The front stop block 46, the middle stop block 44, and therear stop block 42 are attached to the guide 40 in their respectivelocations. The cannula actuator 30 and the stylet actuator 32 slide onan actuator support 80. The actuator support 80 includes two slots 82,84. The projection 64 on the stylet slide 38 extends through and slidesalong the slot 82 such that the stylet actuator 32 engages the styletslide 38. Likewise, the projection 66 on the cannula slide 36 extendsthrough and slides along the slot 84 such that the cannula actuator 30engages the cannula slide 36.

FIG. 7 shows a perspective view of the internal components of analternative embodiment of a biopsy instrument 100 made in accordancewith the principles of the present invention. Components of thealternative biopsy instrument 100 which are similar to the components inbiopsy instrument 10 of FIG. 2 are identified by corresponding numeralsin the 100 series.

The biopsy instrument 100 includes two springs, a stylet spring 186 anda cannula spring 188. The stylet spring 186 is positioned between therear stop block 142 and the stylet slide 138, and biases the styletslide 138 forward. Likewise, the cannula spring 188 is positionedbetween the middle stop block 144 and the cannula slide 136, and biasesthe cannula slide 136 forward. In the fired mode, as shown in FIG. 7,the springs 186, 188 constantly exert forward biasing forces on theslides 138, 136. Accordingly, the first stylet latch on the stylet slide138 has been removed because the stylet spring 186 prevents the stylet122 from recoiling when the cannula 120 is fired.

The biopsy instrument 100 can be placed in a ready mode by actuating thecannula actuator 130 and the stylet actuator 132 in three differentsequences. Referring to FIGS. 7-9, the first actuating or cockingsequence is the same as described above with reference to the instrument10 shown in FIGS. 2-4 in which the cannula actuator 130 is actuatedfirst and independently of the stylet actuator 132, and subsequently thestylet actuator 132 is actuated.

Referring to FIG. 9, the second actuating sequence is simultaneousactuation of the cannula actuator 130 and the stylet actuator 132 by asingle finger while the finger contacts both actuators 130, 132simultaneously. The single finger of the single hand is simultaneouslyplaced on both of the finger surfaces 162. The side-by-side location ofthe actuators 130, 132 allows for the single finger to contact both ofthe finger surfaces 162. As the single finger actuates both actuators130, 132, the stylet 122 and cannula 120 are retracted simultaneously.

The third actuating sequence also simultaneously actuates the cannulaactuator 130 and the stylet actuator 132. The third sequence includes asingle finger contacting only the finger surface 162 of the styletactuator 132. Referring to FIGS. 7 and 9, as the stylet actuator 132 isactuated, a wall 190 on the stylet actuator 132 engages a projection 192on the cannula actuator 130. The projection 192 is shown in FIG. 8.Accordingly, as the stylet actuator 132 slides rearwardly, the cannulaactuator 130 simultaneously slides rearwardly.

Regardless of which actuation sequence is utilized for the instrumentshown in FIGS. 7-9, the stylet 122 cannot be retracted prior toretraction of the cannula 120. This prevents a captured tissue samplefrom being dragged along the inside of the cannula 120 and damaged. Thethree actuating sequences provide medical personnel with flexibility inplacing the biopsy instrument 100 in a ready mode, while, preventingretraction of the stylet 122 prior to retraction of the cannula 120.

While the preferred embodiments have been illustrated and described,numerous changes and modifications can be made without significantlydeparting from the spirit and scope of this invention. Therefore, theinventors intend that such changes and modifications be covered by theappended claims.

What is claimed is:
 1. A biopsy device comprising:a housing; a cannulaslidably extending from the housing through an opening; a styletslidably positioned within the cannula; a stylet actuator associatedwith the stylet, wherein the stylet is retracted within the housing whenthe cannula actuator is actuated; a cannula actuator associated with thecannula, wherein the cannula is retracted within the housing when thecannula actuator is actuated, the cannula and stylet actuatorspositioned laterally relative to each other along a longitudinaldirection of the biopsy device; and, forced generator engagable with thestylet and the cannula, wherein the stylet and the cannula are drivenoutward from the housing by forces released from the force generator. 2.The biopsy device of claim 1 wherein the stylet actuator is adapted tobe actuated with a single finger of a single hand while the hand is in afirst position holding the biopsy device, and the cannula actuator isadapted to be actuated by the same single finger while the hand remainsin the first position.
 3. The biopsy device of claim 1 wherein the forcegenerator comprises a first force generator engagable with the styletand a second force generator engagable with the cannula.
 4. The biopsydevice of claim 1 wherein the force generator is a single spring.
 5. Thebiopsy device of claim 4 wherein the single spring is a constant forcespring.
 6. The biopsy device of claim 1 wherein the stylet actuator andthe cannula actuator are slidable along a longitudinal axis of thehousing.
 7. The biopsy device of claim 6 wherein the stylet and cannulaactuators have juxtaposed sides positioned longitudinally side-by-sideeach other.
 8. The biopsy device of claim 1 wherein the stylet actuatorand the cannula actuator are actuatable in a single sequence by a singlefinger of a single hand, the single sequence comprising actuation of thecannula actuator and subsequent actuation of the stylet actuator.
 9. Thebiopsy device of claim 1 further comprising:a cannula slide attached tothe cannula, the cannula actuator engagable with the cannula slide toretract the cannula; and, a stylet slide attached to the stylet, thestylet actuator engagable with the stylet slide to retract the stylet.10. The biopsy device of claim 1 further comprising a trigger engagablewith a latch associated with the stylet to release the stylet from alatched position.
 11. The biopsy device of claim 10 further comprising asafety cover connected to the housing and moveable from a safetyposition which prevents movement of the trigger to a firing positionwhich allows movement of the trigger.
 12. A biopsy device comprising:acannula permanently secured within a housing and slidably extendingthrough a first end of the housing; a stylet permanently secured withinthe housing and slidably extending through the first end within thecannula; and, a spring alternately biased against both the stylet andthe cannula, wherein the stylet, and the cannula are slid toward thefirst end when the spring is biased against the stylet and the cannularespectfully.
 13. The biopsy device of claim 12 further comprising:acannula actuator engagable with the cannula to move the cannula from afirst position to a second position; and, a stylet actuator engagablewith the stylet to move the stylet from a first position to a secondposition.
 14. The biopsy device of claim 13 further comprising:a styletslide attached to the stylet and slidable between a first positionadjacent a rear stop block and a second position adjacent a middle stopblock; and, a cannula slide attached to the cannula and slidable betweena first position adjacent the middle stop block and a second positionadjacent a front stop block.
 15. The biopsy device of claim 12 furthercomprising a trigger engagable with a latch associated with the styletto release the stylet from a latched position wherein the springadvances the stylet toward the first end.
 16. The biopsy device of claim15 further comprising a safety cover connected to the housing andmoveable from a safety position which prevents movement of the triggerto a firing position which allows movement of the trigger.
 17. Thebiopsy device of claim 12 wherein the spring comprises at least oneconstant force spring.
 18. The biopsy device of claim 12 furthercomprising an engagement mechanism attached to the spring, theengagement mechanism alternatively interlockable with a stylet slideattached to the stylet and abuttable with a cannula slide attached tothe cannula.
 19. The biopsy device of claim 18 further comprising a rampconnected to the housing and wherein the engagement mechanism comprisesa cam surface which cams along the ramp to alternatively interlock andrelease the engagement mechanism with the stylet slide.
 20. The biopsydevice of claim 19 further comprising two spaced apart ramps and whereinthe interlock mechanism cams along both ramps.
 21. A biopsy devicecomprising:a stylet slidably positioned within a cannula, wherein thestylet and the cannula are biased toward one end of the biopsy device byat least one spring; a stylet actuator associated with the stylet tomove the stylet from a first stylet position to a second styletposition; and, a cannula actuator associated with the cannula to movethe cannula from a first cannula position to a second cannula position;wherein the stylet and cannula actuators are positioned transverselyside-by-side each other such that the stylet actuator is adapted to beactuated with a single finger of a single hand while the hand is in afirst position holding the biopsy device, and the cannula actuator isadapted to be actuated by the same single finger while the hand remainsin the first position.
 22. A biopsy device comprising:a cannula slidablyextending through an opening in a housing; a stylet slidably positionedwithin the cannula; at least one spring engagable with the stylet andthe cannula, wherein the stylet and the cannula are driven through theopening when engaged with the at least one spring; a stylet actuatorhaving a first longitudinal side, the stylet actuator associated withthe stylet to retract the stylet within the housing; and, a cannulaactuator having a second longitudinal side, the cannula actuatorassociated with the cannula to retract the cannula within the housing,wherein the first longitudinal side of the stylet actuator faces thesecond longitudinal side of the cannula actuator.
 23. A biopsy devicecomprising:a stylet slidably positioned within a cannula along alongitudinal axis; at least one spring engagable with the stylet and thecannula, wherein the stylet and the cannula are driven along the axiswhen engaged with the at least one spring; a cannula actuator associatedwith the cannula, the cannula actuator having a first end movable from afirst reference plane perpendicular to the axis to a second referenceplane perpendicular to the axis, the second reference plane spaced alongthe axis from the first reference plane; and, a stylet actuatorassociated with the stylet, the stylet actuator having a first endmovable from the first reference plane to the second reference plane.24. A soft tissue biopsy device comprising:a housing having a first endand a second end; a cannula slidably extending through the first end; astylet having a tissue sampling recess, the stylet slidably extendingthrough the first end within the cannula; a stylet slide attached to thestylet and slidable between a first position adjacent a rear stop blockand a second position adjacent a middle stop block; a cannula slideattached to the cannula and slidable between a third position adjacentthe middle stop block and a fourth position adjacent a front stop block;a biasing member contained within the housing, wherein the biasingmember biases the stylet slide and the cannula slide toward the firstend; a cannula actuator engagable with the cannula slide to move thecannula slide from the fourth position to the third position; and, astylet actuator engagable with the stylet slide to move the stylet slidefrom the second position to the first position, the stylet and cannulaactuators positioned laterally relative to each other along alongitudinal direction of the soft tissue biopsy device.
 25. A method ofusing a biopsy device comprising the steps of:providing a slidablecannula at an extended position and a slidable stylet within the cannulaat an extended position; moving the cannula from the extended positionto a retracted position against a biasing force of a spring; moving thestylet from the extended position to a retracted position against thebiasing force of the spring which was biased against the cannula duringthe step of moving the cannula from the extended position to theretracted position; moving the stylet from the retracted position to theextended position by using the biasing force of the spring which wasbiased against both the cannula and stylet during the steps of movingthe cannula and stylet from the extended positions to the retractedpositions, and, moving the cannula from the retracted position to theextended position by using the biasing force of the spring which wasbiased against the stylet during the step of moving the stylet from theretracted position to the extended position.
 26. A method of firing abiopsy device comprising the steps of:providing a slidable cannula at afirst cannula position and a slidable stylet within the cannula at afirst stylet position; moving the stylet from the first stylet positionto a second stylet position by a biasing force of a spring; moving thecannula from the first cannula position to a second cannula positionsimultaneously during a portion of the stylet movement; and, moving thecannula from the second cannula position to a third cannula position bythe biasing force of the spring.
 27. A method of placing a biopsy devicein a ready mode comprising the steps of:providing a slidable cannula ata first cannula position and a slidable stylet within the cannula at afirst stylet position; holding the biopsy device with a single hand in afirst hand position; moving a cannula actuator to move the cannula fromthe first cannula position to a second cannula position with a finger ofthe hand while the hand remains in the first hand position; and, movinga stylet actuator transversely juxtaposed the cannula actuator to movethe stylet from the first stylet position to a second stylet positionwith the finger of the hand while the hand remains in the first handposition.
 28. The biopsy device of claim 1 wherein the force generatorcomprises at least one constant force spring.
 29. The biopsy device ofclaim 21 wherein the at least one spring is attached to an engagementmechanism which releasably interlocks with the stylet.
 30. The biopsydevice of claim 22 wherein the at least one spring is attached to anengagement mechanism which releasably interlocks with the stylet. 31.The biopsy device of claim 23 wherein the at least one spring isattached to an engagement mechanism which releasably interlocks with thestylet.
 32. The biopsy device of claim 24 wherein the biasing member isattached to an engagement mechanism which releasably interlocks with thestylet.
 33. The method of claim 25 wherein the step of moving thecannula from the extended position to a retracted position comprises thestep of moving a cannula actuator engaged with the cannula, and the stepof moving the stylet from the extended position to a retracted positioncomprises the step of moving a stylet actuator engaged with the styletand positioned transversely adjacent the cannula actuator.
 34. Themethod of claim 27 wherein the steps of moving the cannula and styletactuators further comprises moving the stylet and cannula actuatorsagainst biasing forces of a spring.
 35. The biopsy device of claim 12wherein the spring is formed by a plurality of springs connectedtogether.
 36. The biopsy device of claim 12 wherein the spring isconcurrently biased against the stylet and the cannula during a portionof travel of the stylet and a portion of travel of the cannula.